Numerous drywall panel lifters are known in the art. Among them is U.S. Pat. No. 7,101,136 to Ray et al, for Drywall Panel Carrier. This reference discloses a panel lifter having a pair of panel-supporting legs of square tubing attachable to side rails of a lift platform. Each leg is connected to the rails by an upper bracket at the top of the leg and a lower bracket at a middle location. A panel-receiving U-shaped channel is located on the opposite side of the legs, away from the rails. The lower bracket has a standoff member projecting the bottom of the leg outward at an angle. A roller at the base of the channel provides low-friction rolling contact with an inserted panel, and a groove in this roller serves to guide the panel. Rollers at the tops of the legs and elsewhere are placed to keep panels from being damaged by contact with the legs.
U.S. Pat. No. 6,773,218 to Mingoes, for Adjustable Ceiling Panel Lifting Apparatus discloses a device having lift support assemblies each including a support base member and a pair of support rail members being spaced apart and extending upwardly from the support base members. The lift support assemblies are mounted on wheel assemblies. Lift actuating members are engaged to and raise and lower the lift members. Elongate support members interconnect the lift support assemblies.
U.S. Pat. No. 6,244,810 to Reyes, for Drywall Handyman discloses a device for elevating drywall onto a ceiling at various angles. The device includes a base member, a telescoping member secured to said base member projecting upwardly, a disc pivotally attached to the telescoping member opposite the base member, a support member secured to the pivoting assembly allowing coupling to the drywall, a crank pivotally secured within the lower portion of the telescoping-member, a pulley secured to the upper portion of the telescoping member, and a cable engaging the crank, projecting through the pulley and engaging and extending the telescoping member.
U.S. Pat. No. 4,375,934 to Elliott, for Lifting and Positioning Apparatus for Construction Panels discloses an apparatus including a base, a fixed strut supported vertically from the base, a movable strut supported from the fixed strut, a guide and latch arrangement for retaining the struts in generally parallel relationship, a handle on the movable strut for elevating same in relation to the fixed strut and the base, and a panel engaging rail supported on the movable strut. The panel engaging rail may be supported at the top of the movable strut, in which case, two of the standards are used to elevate and position a panel against the underside of a ceiling framework.
Commercially available drywall panel lifters include the Buffalo Tools DWHOIST Drywall Lift Hoist from www.constructioncomplete.com and the Telpro Drywall PANELLIFT from www.all-wall.com. Each consists of a stanchion mounted on a tripod, each leg of which is fitted with a 5-inch caster. The drywall panel is held by a U-shaped bracket and supported by an H-shaped beam structure. Once placed on the device, a fast action, single-stage winch equipped with a cam lock brake lifts the supporting structure to position the panel where desired.